This section provides background information related to the present disclosure which is not necessarily prior art.
A standing wave can also be referred to as a stationary wave. Generally, a standing or stationary wave can be formed from various mechanics, including interference between two waves. For example, two opposing waves can move towards one another in a medium and cause the formation of a standing wave. Alternatively, or in addition to the opposing waves, a medium can move in a direction opposite the wave to cause a standing wave. Generally, the standing wave, or wave pattern, includes a wave node (a point where the wave has zero amplitude) and a wave anti-node (where a wave has a maximum amplitude) relative to an axis.
Waves can be generated as surface waves, including surface acoustic waves. The surface acoustic waves can also be generated as standing surface acoustic waves. A surface wave may be a wave that is generated on or within a surface or substrate that may then interact with a material within a space and/or a channel formed on or in the substrate.
Pumps may be used to deliver the material to the substrate. However, many pumps, such as various rotary pumps, pump fluid in a pulsed flow. A pulsed flow would be disadvantageous when delivering a material into a standing wave because it can cause unwanted disruptions in the material between pulses. Therefore, a rotary pump that pumps fluid in a continuous flow is desirable for delivering a material into a substrate wherein the material interacts with a surface wave. Additionally, devices for generating a steady flow rate from a pulsed flow rate provided by a pump are also desired.